Mike, should be no problem. I have had a "Skippy" for several years. A few inches off the bottom is good. Be sure you have a bottom drain with a shut-off that you can open once a week to pull out any sediment in the bottom. I usually do it when I'm doing a water change. And don't believe that it never needs cleaning! Mine works well on a once a year fall cleaning and an occasional draindown flush. I have my media in bags and shake them a tub of pond water. Depending on the media and the pond ( fish load, plantings), you may have clean more often. Rule of thumb- when you get about 1/4 of crud on media or waterfall seems slower - time to clean!
Ed